腾讯云通信UserSig生成.Net实现

腾讯云通信后台生成usersig只有java实现代码。以下是根据java代码转换为net实现，java版GitHub地址：https://github.com/TencentVideoCloudMLVBDev/usersig_server_source/blob/master/java/WebRTCSigApi.java。

需要使用类库：Portable.BouncyCastle，SharpZipLib，直接从nuget下载安装即可。

另外我正在实现腾讯云IM服务端Sdk .NetCore版本，github地址：https://github.com/yangxuilyx/QCloudIM.AspNetCore

 public class TlsSignature
    {
        /// <summary>
        /// 获取用户sign
        /// </summary>
        /// <param name="appid">appid</param>
        /// <param name="privateKey">私钥</param>
        /// <param name="userid">用户名</param>
        /// <param name="expire">userSig有效期，出于安全考虑建议为300秒，您可以根据您的业务场景设置其他值。</param>
        /// <returns>生成的userSig</returns>
        public static string GenUserSig(string appid, string privateKey, string userid, int expire)
        {
            
            var time = (DateTime.Now.ToUniversalTime().Ticks - 621355968000000000) / 10000000;
            String serialString =
                "TLS.appid_at_3rd:" + 0 + "
" +
                "TLS.account_type:" + 0 + "
" +
                "TLS.identifier:" + userid + "
" +
                "TLS.sdk_appid:" + appid + "
" +
                "TLS.time:" + time + "
" +
                "TLS.expire_after:" + expire + "
";

            var sign = Convert.ToBase64String(Sign(privateKey, Encoding.UTF8.GetBytes(serialString)));

            String jsonString = "{"
                                + ""TLS.account_type":"" + 0 + "","
                                + ""TLS.identifier":"" + userid + "","
                                + ""TLS.appid_at_3rd":"" + 0 + "","
                                + ""TLS.sdk_appid":"" + appid + "","
                                + ""TLS.expire_after":"" + expire + "","
                                + ""TLS.sig":"" + sign + "","
                                + ""TLS.time":"" + time + "","
                                + ""TLS.version": "201512300000""
                                + "}";

            var compressBytes = Compress(Encoding.UTF8.GetBytes(jsonString));

            var userSign = Base64UrlEncode(compressBytes);
            return userSign;
        }

        private static byte[] Compress(byte[] data)
        {
            Deflater mDeflater = new Deflater();
            mDeflater.SetInput(data);
            mDeflater.Finish();
            byte[] compressBytes = new byte[512];
            int compressBytesLength = mDeflater.Deflate(compressBytes);

            mDeflater.Flush();

            return compressBytes.Take(compressBytesLength).ToArray();
        }

        /// <summary>
        /// ECDSA-SHA256签名
        /// </summary>
        /// <param name="privateKey">私钥</param>
        /// <param name="data">需要签名的数据</param>
        /// <returns></returns>
        private static byte[] Sign(string privateKey, byte[] data)
        {
            ECPrivateKeyParameters privateKeyParam = (ECPrivateKeyParameters)PrivateKeyFactory.CreateKey(Convert.FromBase64String(privateKey));

            var signer = SignerUtilities.GetSigner("SHA256withECDSA");
            signer.Init(true, privateKeyParam);
            signer.BlockUpdate(data, 0, data.Length);

            return signer.GenerateSignature();
        }

        /// <summary>
        /// 验证ECDSA-SHA256签名
        /// </summary>
        /// <param name="publicKey">公钥</param>
        /// <param name="data">需要验证的数据原文</param>
        /// <param name="sig">需要验证的签名</param>
        /// <returns>true:验证成功 false:验证失败</returns>
        public static bool Verify(string publicKey, byte[] data, byte[] sig)
        {
            ECPublicKeyParameters publicKeyParam = (ECPublicKeyParameters)PublicKeyFactory.CreateKey(Convert.FromBase64String(publicKey));

            var signer = SignerUtilities.GetSigner("SHA256withECDSA");
            signer.Init(false, publicKeyParam);
            signer.BlockUpdate(data, 0, data.Length);

            return signer.VerifySignature(sig);

        }

        private static string Base64UrlEncode(byte[] data)
        {
            return Convert.ToBase64String(data).Replace('+', '*').Replace('/', '-')
                 .Replace('=', '_');
        }

        private static string Base64UrlDecode(byte[] data)
        {
            return Convert.ToBase64String(data).Replace('*', '+').Replace('-', '/')
                .Replace('_', '=');
        }
    }